Voice over Internet Protocol (VOIP) Gateways (GWs) provide telephone voice services replacing traditional long-distance circuit switches. A traditional telephone system also provides the ability for users with modems to connect to a Remote Access Server (RAS) for digital communications over standard voice lines. This same capability is provided by VOIP Gateways through the use of a Modem Passthrough (MPT) or Voice Band Data (VBD) mode. From voice mode, after a VOIP gateway detects a 2100 Hz tone and phase reversal, it (i) switches into VBD mode by disabling its echo canceller and data compressor and (ii) uses the G.711 standard as the voice Coder/Decoder (CODEC), which provides a clear digital channel. From the VBD mode, the VOIP GW normally switches back to voice mode by sensing voice in the signal through use of a voice detector.